1. Field of the Invention
The present invention relates in general to door lock assemblies and more particularly to automotive door lock assemblies of a power type, which comprises a door lock device and an electric actuator for actuating the door lock device.
2. Description of Related Art
Hitherto, various types of door lock assemblies have been put into practical use particularly in the field of wheeled motor vehicles. Some of them are of a type which comprises a lock/unlock mechanism that can switch between lock and unlock conditions, and an electric actuator that forces the lock/unlock mechanism to switch between the lock and unlock conditions with an electric force. That is, in the lock condition of the mechanism, an outside door handle is inoperative and thus the door can not be opened even if the door handle is manipulated, while, in the unlock condition of the mechanism, the outside door handle is operative and thus manipulation of the handle can induce opening of the door.
Recently, some of the door lock assemblies have a so-called xe2x80x9ckeyless entry systemxe2x80x9d incorporated therewith. In this system, a wireless control is used for operating the electric actuator to force the lock/unlock mechanism to switch between the lock and unlock conditions. One of such entry systems is of a type which comprises a portable signal transmitter carried by an operator (viz., driver), a signal receiver installed in the vehicle and a control unit installed in the vehicle for controlling the electric actuator in accordance with a code signal received by the signal receiver. That is, when the operator (viz., driver) carrying the transmitter approaches the vehicle door and manipulates the outside door handle of the vehicle, the signal receiver detects the code signal from the transmitter and the control unit issues an instruction signal to the electric actuator to assist the door opening manipulation of the driver. More specifically, upon sensing the code signal, the electric actuator is energized to force the lock/unlock mechanism to switch from the lock condition to the unlock condition. Thus, thereafter, the door can be opened by a continued manipulation of the door handle by the operator.
In the above-mentioned door lock assembly incorporated with the keyless entry system, speedy switching from the lock condition to the unlock condition is inevitably needed by the lock/unlock mechanism because the manipulation of the outside handle by the operator (viz., driver) is usually made right after the signal receiver receives the code signal from the transmitter. For achieving the quick switching, the known door lock assembly uses a high power electric actuator. However, as is known, usage of such high power actuator tends to bring about increase in cost of the door lock assembly as well as increase in size of the same.
It is therefore an object of the present invention to provide an automotive door lock assembly of a power type, which is free of the above-mentioned drawbacks.
That is, according to the present invention, there is provided an automotive door lock assembly of a power type, which can quickly switch the lock/unlock mechanism from the lock condition to the unlock condition without using a high power electric actuator.
According to a first aspect of the present invention, there is provided an automotive door lock assembly which comprises a lock unlock mechanism including a lock/unlock lever and a sub-lever, the lock/unlock mechanism being able to switch between a lock condition wherein both the lock/unlock lever and sub-lever assume respective lock positions to induce a locked condition of the door and an unlock condition wherein both the lock/unlock lever and sub-lever assume respective unlock positions to induce an unlocked condition of the door; an electric actuator which forces the lock/unlock mechanism to switch between the lock and unlock conditions with an electric force; and a structure including a passive lever and a biasing means which are incorporated with the door lock assembly, the passive lever being actuated by the electric actuator and shifted, at an initial stage of the operation of the electric actuator for shifting the lock/unlock mechanism to the unlock condition, from an engaged position where the lock/unlock lever and the sub-lever are engaged to move together to a disengaged position where the engagement between the lock/unlock lever and the sub-lever is canceled, wherein when the passive lever is shifted to the disengaged position, the sub-lever is shifted to the unlock position by the biasing means prior to shifting of the lock/unlock lever to the unlock position from the lock position by the electric actuator.
According to a second aspect of the present invention, there is provided an automotive door lock assembly which comprises a lock/unlock mechanism including a lock/unlock lever and a sub-lever which are each movable between lock and unlock positions, the lock/unlock mechanism being able to switch between a lock condition wherein both the lock/unlock lever and sub-lever assume respective lock positions to induce a locked condition of the door, an unlock condition wherein both the lock/unlock lever and sub-lever assume respective unlock positions to induce an unlocked condition of the door and a temporary unlocked condition wherein the lock/unlock lever assumes the lock position or a position between the lock and unlock positions and the sub-lever assumes the unlock position to induce an unlocked condition of the door; a passive lever movably connected to one of the lock/unlock lever and the sub-lever, the passive lever being movable between an engaged position where the passive lever engages with a stopper portion provided on the other of the lock/unlock lever and the sub-lever thereby to engage the lock/unlock lever with the sub-lever and a disengaged position where the passive lever disengages from the stopper portion thereby to permit the lock/unlock mechanism to switch from the lock condition to the temporary unlocked condition; biasing means which biases the sub-lever toward the unlock position with respect to the lock/unlock lever; an electric actuator; an operation lever which is moved by the electric actuator between a lock position to induce the lock condition of the lock/unlock mechanism and an unlock position to induce the unlock condition of the lock/unlock mechanism; and a cancel lever moved by the electric actuator, the cancel lever being capable of shifting the passive lever to the disengaged position from the engaged position prior to the movement of the operation lever to the unlock position from the lock position.